JP4838092B2 - Webbing take-up device - Google Patents

Description

  The present invention relates to a webbing take-up device that can take up a webbing by driving a motor.

  As a webbing take-up device, a return spring applies a biasing force in a take-up direction to a spool around which a webbing (seat belt) is taken up, and a motor is driven in a vehicle emergency to wind the spool via a clutch mechanism. Some webbing is wound up by being rotated in the taking direction (see, for example, Patent Document 1).

Here, in such a webbing take-up device, when a limiting mechanism (so-called tension reducer) for restricting the application of the urging force to the spool by the return spring is provided, it is preferable that the webbing take-up device can be downsized.
Japanese Patent Laid-Open No. 2002-2450

  An object of the present invention is to obtain a webbing take-up device that can be downsized in consideration of the above facts.

The webbing take-up device according to claim 1, wherein the webbing is taken up by being rotated in the take-up direction, and the take-up shaft from which the webbing is taken out by being rotated in the take-out direction; An arrangement member on which a shaft is arranged; an urging means connected to the take-up shaft to apply an urging force in the take-up direction to the take-up shaft; and a motor capable of being driven in one direction and the other direction Winding that is arranged outside the arrangement member, is provided between the winding shaft and the motor, and rotates the winding shaft in the winding direction when the motor is driven in one direction. mechanism and the winding mechanism and while being integrally disposed on the outside of the placement member, provided between said winding shaft motor, the biasing by the motor is driven in the other direction to limit the transmission of the biasing force to the winding shaft from the means While limiting the application of the biasing force to the winding shaft according to the serial biasing means, the motor permits the transfer of biasing force from the biasing means to the winding shaft by being driven in one direction And a limiting mechanism that permits application of urging force to the winding shaft by the urging means .

  The webbing take-up device according to claim 2 is the webbing take-up device according to claim 1, wherein the take-up mechanism drives the take-up shaft and the motor by driving the motor in one direction. The winding shaft is rotated in the winding direction, and the motor is driven in the other direction to release the communication between the winding shaft and the motor.

  The webbing take-up device according to claim 3 is the webbing take-up device according to claim 1 or 2, wherein the motor is driven in the other direction when the webbing is mounted on an occupant, and The motor is driven in one direction when the webbing is released from the occupant.

  In the webbing take-up device according to claim 1, the take-up shaft is arranged inside the arrangement member, and the webbing is taken up by rotating the take-up shaft in the take-up direction, and the take-up shaft is The webbing is pulled out by rotating in the pull-out direction. Furthermore, the urging means connected to the take-up shaft applies a urging force in the take-up direction to the take-up shaft.

  Further, a winding mechanism is provided between the winding shaft and the motor, and the winding mechanism rotates the winding shaft in the winding direction when the motor is driven in one direction. Furthermore, a limiting mechanism is provided between the winding shaft and the motor, and the limiting mechanism limits the application of the urging force to the winding shaft by the urging means when the motor is driven in the other direction. For this reason, after the motor is driven in one direction and the take-up mechanism rotates the take-up shaft in the take-up direction, the motor is driven in the other direction, so that the limiting mechanism is moved to the take-up shaft by the urging means. The application of the urging force can be limited.

  Here, the winding mechanism and the limiting mechanism are integrally arranged outside the arrangement member. For this reason, a webbing take-up device can be reduced in size.

  In the webbing take-up device according to claim 2, when the motor is driven in one direction, the take-up mechanism connects the take-up shaft and the motor to rotate the take-up shaft in the take-up direction. By being driven in the other direction, the winding mechanism releases the connection between the winding shaft and the motor. For this reason, when the winding mechanism releases the communication between the winding shaft and the motor, the limiting mechanism can limit the application of the urging force to the winding shaft by the urging means.

  In the webbing take-up device according to the third aspect, when the webbing is mounted on the occupant, the motor is driven in the other direction. For this reason, since the restriction mechanism restricts the application of the urging force to the winding shaft by the urging means, the urging force of the urging means acting on the occupant from the webbing can be reduced.

  On the other hand, when the webbing is released from the occupant, the motor is driven in one direction. For this reason, the restriction | limiting by the restriction | limiting mechanism of provision of the urging | biasing force to the winding shaft by the urging | biasing means is cancelled | released, and webbing can be appropriately wound around a winding shaft with the urging | biasing force of an urging | biasing means.

  FIG. 1 is a front view showing an outline of the overall configuration of a motor retractor 10 as a webbing take-up device according to an embodiment of the present invention. FIG. 2 shows an overview of the overall configuration of the motor retractor 10. It is shown in an exploded perspective view. Further, FIG. 3 shows an exploded perspective view of the main part of the motor retractor 10, and FIG. 4 shows a cross-sectional view of the main part of the motor retractor 10.

  The motor retractor 10 according to the present embodiment includes a frame 12 having a U-shaped cross section as an arrangement member. The frame 12 is provided with a flat back plate 14. The motor retractor 10 is fixed to the vehicle body via the frame 12 by fixing the back plate 14 to the vehicle body by fastening means (not shown) such as bolts. ing. From the other side (arrow B side) end and one side (arrow A side) end of the back plate 14, a pair of flat leg pieces 16, 18 are respectively extended on the same side, and the pair of leg pieces 16. , 18 are perpendicular to the back plate 14 and parallel to each other.

  In the frame 12, a substantially circular spool 20 as a take-up shaft is rotatably disposed between the pair of leg pieces 16 and 18, and the spool 20 is manufactured by die casting or the like. A shaft-shaped adapter 24 is integrally and coaxially provided on the spool 20, and the adapter 24 protrudes from the spool 20 to the other side (arrow B side) and is outside the frame 12 (other than the leg pieces 16). Side (arrow B side).

  A base end portion of a webbing 28 (seat belt) formed in a long band shape is fixed to the spool 20, and when the spool 20 is rotated in the winding direction (arrow G direction), the webbing 28 is It is wound up in layers on the outer periphery of the spool 20 from the side. Further, when the webbing 28 is pulled from the front end side, the webbing 28 wound around the outer periphery of the spool 20 is pulled out from the spool 20, and accordingly, the spool 20 rotates in the pull-out direction (arrow H direction).

  A case 22 is fixed to the outside of the frame 12 on one side of the leg piece 18 (arrow A side). A lock mechanism (not shown) is accommodated in the case 22, and the lock mechanism normally allows free rotation in the winding direction (arrow G direction) and the drawing direction (arrow H direction) of the spool 20, When the vehicle is in an emergency (for example, when the vehicle collides), the spool 20 is prevented from rotating in the pull-out direction (arrow H direction).

  A case 32 as a housing member is fixed to the outside of the frame 12 on the other side (arrow B side) of the leg piece 16. As shown in detail in FIGS. 5 and 7, the case 32 is formed with a substantially cylindrical first housing portion 38, and the first housing portion 38 is opened on one side (arrow A side), It is closed from one side (arrow A side) by a cover 34 screwed to the case 32. The adapter 24 of the spool 20 is rotatably passed through the cover 34, and the adapter 24 is disposed in the first housing portion 38. Further, the case 32 is formed with a second housing portion 40, and the second housing portion 40 is opened on the other side (arrow B side) and is covered with the cover 36 screwed to the case 32 on the other side ( It is closed from the arrow B side.

  In the first housing portion 38 of the case 32, a metal plate-like drive gear 46 constituting the winding mechanism 42 is housed on one side (arrow A side), and the drive gear 46 is a spur gear. It is said that. The drive gear 46 is integrally and coaxially connected to the adapter 24 of the spool 20, and the drive gear 46 can be rotated integrally with the spool 20 via the adapter 24.

  In the first housing portion 38 of the case 32, a spiral spring 44 as a biasing means is housed in the other side (arrow B side) portion. The spiral spring 44 has an inner end that is locked to the adapter 24 of the spool 20 and an outer end that is locked to the outer periphery of the first accommodating portion 38, and the spiral spring 44 is connected to the spool 20 via the adapter 24. It is energized in the winding direction (arrow G direction). As a result, the webbing 28 pulled out from the spool 20 can be wound up by the urging force of the spiral spring 44 so that the entire amount of the webbing 28 (the total amount that can be wound up) is resisted against the frictional force with the vehicle.

  In the first housing portion 38 of the case 32, a substantially bottomed cylindrical limiting body 62 as a limiting member constituting a tension reducer mechanism 60 as a limiting mechanism is accommodated between the drive gear 46 and the spiral spring 44. The restriction body 62 is coaxially supported by the adapter 24 of the spool 20, and the restriction body 62 is rotatable with respect to the spool 20 (adapter 24). A plurality of plate-like restricting convex portions 64 are continuously formed on the outer periphery of the restricting body 62, and the restricting convex portions 64 protrude from the restricting body 62 radially outward in a trapezoidal shape on the outer surface and are wound up. The direction (arrow G direction) side surface has a smaller angle with respect to the radially outward direction of the restricting body 62 than the drawing direction (arrow H direction) side surface.

  The adapter 24 of the spool 20 supports a torsion coil spring 66 as a limit urging means constituting the tension reducer mechanism 60 inside the restricting body 62, and one end of the torsion coil spring 66 is engaged with the adapter 24. While being stopped, the other end is locked to the restriction body 62. Thereby, the limiting body 62 is made rotatable with the spool 20 (adapter 24).

  A motor 48 is fixed to one surface (arrow A side) of the case 32, and the motor 48 is disposed between the pair of leg pieces 16 and 18 of the frame 12. The output shaft 50 of the motor 48 protrudes from the motor 48 to the other side (arrow B side) and penetrates the case 32. The output shaft 50 is housed in the second housing portion 40 of the case 32 and the output shaft 50. An output gear 52, which is a spur gear, is fixed to the.

  As shown in detail in FIGS. 6 and 8, a drive gear 56 as a drive member constituting the tension reducer mechanism 60 is accommodated in the second accommodating portion 40 of the case 32, and the drive gear 56 has an axial center. The portion is rotatably supported by a support shaft 58 attached to the case 32, and is rotatably supported by the case 32. The drive gear 56 is a spur gear, the outer periphery is meshed with the output gear 52 of the motor 48, the motor 48 is driven in the forward direction (the other direction), and the output shaft 50 and the output gear 52 are either one around the axis ( When rotated in the direction of arrow C), the drive gear 56 is rotated around one axis (in the direction of arrow E) and the motor 48 is driven in the opposite direction (one direction) to output the output shaft 50 and the output gear 52. Is rotated around the axis in the other direction (arrow D direction), the drive gear 56 can be rotated around the axis in the other direction (arrow F direction).

  The drive gear 56 is coaxially formed with a cylindrical slip recess 68 that constitutes the slip means of the tension reducer mechanism 60, and the slip recess 68 is opened from the drive gear 56 to one side (arrow A side). Yes. The slip recess 68 accommodates a substantially cylindrical slip spring 70 as slip biasing means constituting the slip means, and the slip spring 70 is elastically contacted with the inner peripheral surface of the slip recess 68 by the biasing force. Thus, the drive gear 56 can rotate integrally with the frictional force between the slip recess 68 and the inner peripheral surface. A portion of the slip spring 70 in the circumferential direction is separated, and a flat plate-like insertion plate 70A is bent on both sides of the separation portion in the circumferential direction.

  A cam 72 as an operating member constituting the tension reducer mechanism 60 is disposed on one side (the arrow A side) of the drive gear 56, and the cam 72 is rotatably supported by the support shaft 58 at the shaft center portion. The case 32 is rotatably supported.

  The other side (arrow B side) portion of the cam 72 is formed into a substantially cylindrical shape and is inserted into the slip spring 70 in the slip recess 68 of the drive gear 56, and the other side (arrow B side) portion of the cam 72. A pair of insertion recesses 72 </ b> A are formed on the outer periphery. A pair of insertion plates 70A of slip springs 70 are inserted into the pair of insertion recesses 72A, respectively, so that the cam 72 can rotate integrally with the slip springs 70.

  The cam 72 is formed with a columnar cam portion 74 at an intermediate portion between the one side (arrow A side) portion and the other side (arrow B side) portion. The diameter of the cam portion 74 is the smallest diameter portion. Is gradually increased from one to the other around the axis (in the direction of arrow F).

  On one side (arrow A side) of the cam 72, an elliptical columnar locking projection 76 constituting slip means is formed, and the locking projection 76 projects from the cam 72 to one side (arrow A side). Yes. Corresponding to the locking projection 76, a locking recess 78 having a substantially circular shape in front view constituting the slip means is formed on one side (arrow A side) surface (bottom surface) of the second housing portion 40, A part of the locking recess 78 in the circumferential direction is separated. A locking projection 76 of the cam 72 is inserted into the locking recess 78, and the locking projection 76 can revolve along the locking recess 78 by rotating the cam 72.

  Here, the drive gear 56, the slip spring 70, and the cam 72 are rotated around one axis (in the direction of arrow E), and the locking projection 76 abuts on one end (in the direction of arrow E) around the axis of the locking recess 78. Then, the cam 72 and the slip spring 70 are prevented from rotating in one direction (arrow E direction), and the drive gear 56 is rotated relative to the slip spring 70 and the cam 72 in one direction (arrow E direction) (slip). ) Thereby, the maximum diameter portion of the cam portion 74 faces the restriction body 62.

  On the other hand, when the drive gear 56, the slip spring 70, and the cam 72 are rotated around the axis in the other direction (arrow F direction), the locking projection 76 comes into contact with the other end (arrow F direction) side end around the axis of the locking recess 78. Then, the rotation of the slip spring 70 and the cam 72 around the axis (the direction of the arrow F) is prevented, and the drive gear 56 rotates relative to the slip spring 70 and the cam 72 around the axis (the direction of the arrow F) (slip). Is done. Thereby, the minimum diameter portion of the cam portion 74 faces the restricting body 62.

  A pawl mechanism 80 serving as a locking means constituting the tension reducer mechanism 60 is accommodated in the second housing portion 40 of the case 32. The pawl mechanism 80 includes a first pawl 82 serving as a first locking member. The first pawl 82 is rotatably supported by the case 32 with one end rotatably supported by a support shaft 26 attached to the case 32. The pawl mechanism 80 is provided with a second pawl 84 as a second locking member. One end of the second pawl 84 is rotatably supported near one end of the first pawl 82.

  The pawl mechanism 80 is provided with a return spring 54 as a locking urging means. The return spring 54 is a torsion coil spring supported by the support shaft 26, and one end of the second housing portion 40. Locked to the outer peripheral surface. The other end of the return spring 54 is passed through an elliptical elongated hole 82 </ b> A formed through the first pawl 82 to be locked to the first pawl 82, and a circular recess formed in the second pawl 84. 84A and is locked to the second pawl 84, whereby the return spring 54 biases the first pawl 82 and the second pawl 84 in the direction in which the first pawl 82 and the second pawl 84 are rotated to the opposite side of the restricting body 62. Thus, the other end of the first pawl 82 is brought into contact with the cam portion 74 of the cam 72, and the second pawl 84 is biased in a direction in which the second pawl 82 is rotated toward the restricting body 62. Further, the second accommodating portion 40 is communicated with the first accommodating portion 38 in the vicinity of the other end of the second pawl 84, and the other end of the second pawl 84 is configured to come into contact with the outer periphery of the restricting body 62. .

  As shown in FIG. 9A, the cam 72 is rotated around the axis in the other direction (in the direction of arrow F), and the locking projection 76 comes into contact with the other end (in the direction of arrow F) around the axis of the locking recess 78 to form the cam portion. When the minimum diameter portion 74 is opposed to the restricting body 62, the first pawl 82 and the second pawl 84 are disposed at the rotation position on the opposite side of the restricting body 62 by the urging force of the return spring 54, and the second The other end of the pawl 84 is separated from the outer periphery of the restricting body 62. For this reason, the spool 20 (adapter 24), the torsion coil spring 66, and the restricting body 62 are integrally rotatable.

  On the other hand, as shown in FIGS. 9B and 9C, the cam 72 is rotated around one axis (in the direction of arrow E) and the locking projection 76 is rotated around the axis of the locking recess 78 (in the direction of arrow E). When the maximum diameter portion of the cam portion 74 is in contact with the side end and faces the restricting body 62, the first pawl 82 and the second pawl 84 are rotated on the restricting body 62 side against the urging force of the return spring 54. The other end of the second pawl 84 is brought into contact with the outer periphery of the restricting body 62, being arranged at the moving position.

  Therefore, as shown in FIG. 9B, when the limiting body 62 is rotated in the winding direction (arrow G direction) together with the spool 20 (adapter 24) by the biasing force of the spiral spring 44, the limiting body 62 The surface of the restricting convex portion 64 on the winding direction (arrow G direction) side is locked to the other end of the second pawl 84, and the restriction body 62 is prevented from rotating in the winding direction (arrow G direction). . Accordingly, the spool 20 (adapter 24) is pulled out by the biasing force of the torsion coil spring 66 as the spool 20 (adapter 24) is rotated in the winding direction (arrow G direction) by the biasing force of the spiral spring 44. The rotational force in the (arrow H direction) increases, and the rotational force in the winding direction (arrow G direction) of the spool 20 due to the urging force of the spiral spring 44 is limited by the urging force of the torsion coil spring 66. The rotational force in the winding direction (arrow G direction) is weakened.

  Further, as shown in FIG. 9C, the webbing 28 is pulled out from the spool 20 and compared with the rotational force in the winding direction (arrow G direction) of the spool 20 (adapter 24) by the urging force of the spiral spring 44. The rotational force in the pull-out direction (arrow H direction) of the spool 20 (adapter 24) due to the urging force of the torsion coil spring 66 increases, and the restricting body 62 is pulled out (arrow H direction) by the urging force of the torsion coil spring 66. When the second pawl 84 is rotated to the first pawl 82, the second pawl 84 is guided by the surface of the restricting protrusion 64 of the restricting body 62 on the pulling direction (arrow H direction) side and resists the urging force of the return spring 54. On the other hand, by rotating to the opposite side of the restricting body 62, the restricting convex portion 64 gets over the other end of the second pawl 84 and the restriction body 62 is allowed to rotate in the pull-out direction (arrow H direction). . Thereby, the rotational force in the pulling-out direction (arrow H direction) of the spool 20 by the biasing force of the torsion coil spring 66 is compared with the rotational force in the winding direction (arrow G direction) of the spool 20 by the biasing force of the spiral spring 44. Is prevented from becoming large.

  Further, an overload mechanism 86 constituting the winding mechanism 42 is provided in the second housing portion 40 of the case 32. The overload mechanism 86 has an intermediate gear 88 which is formed in a bottomed cylindrical shape and has an inside opened to the other side (arrow B side). The intermediate gear 88 is rotatably supported by a support shaft 90 attached to the case 32 at an axial center, and is rotatably supported by the case 32. Further, spur external teeth 92 are formed on the outer peripheral portion of the intermediate gear 88, and the external teeth 92 are engaged with the output gear 52 of the motor 48. For this reason, when the motor 48 is driven in the forward direction and the output shaft 50 and the output gear 52 are rotated around one axis (in the direction of arrow C), the intermediate gear 88 is rotatable around one axis (in the direction of arrow I). At the same time, when the motor 48 is driven in the opposite direction and the output shaft 50 and the output gear 52 are rotated around the axis in the other direction (arrow D direction), the intermediate gear 88 can be rotated around the axis in the other direction (arrow J direction). Has been.

  An adapter 94 constituting an overload mechanism 86 is provided on the other side (arrow B side) of the intermediate gear 88. The adapter 94 has a flange portion 96 that is formed in a disk shape and is rotatably fitted to the opening of the intermediate gear 88. Further, on the other side of the flange portion 96 (arrow B side), a gear portion 98 formed in a columnar shape is formed so as to protrude coaxially. Flat teeth 100 are formed on the outer periphery of the gear portion 98. Further, on one side (arrow A side) of the flange portion 96, a holding portion 102 that is formed in a columnar shape and is accommodated in the intermediate gear 88 is coaxially formed.

  An annular gap is formed between the outer peripheral surface of the holding portion 102 and the inner peripheral surface of the intermediate gear 88. The overload mechanism 86 is formed in this gap in a spiral shape by a metal wire. A clutch spring 104 serving as a slip member is accommodated. The clutch spring 104 is formed so that its inner diameter is slightly smaller than the outer diameter of the holding portion 102, and its inner peripheral portion is brought into close contact with the outer peripheral surface of the holding portion 102 by its own elastic force. The portion 102 is connected (held) by frictional force. For this reason, the clutch spring 104 basically rotates integrally with the intermediate gear 88.

  In addition, the clutch spring 104 is restricted from rotating relative to the intermediate gear 88 because both ends in the winding direction interfere with the inner peripheral surface of the intermediate gear 88. Therefore, the intermediate gear 88 and the adapter 94 are connected via the clutch spring 104. When the intermediate gear 88 rotates, the clutch spring 104 and the adapter 94 rotate. However, as described above, the clutch spring 104 is configured to be held by the frictional force with respect to the adapter 94, and therefore, when a relative rotational force exceeding the frictional force acts between the intermediate gear 88 and the adapter 94. When the clutch spring 104 slips with respect to the adapter 94, the intermediate gear 88 and the clutch spring 104 and the adapter 94 are idled relatively.

  As shown in FIG. 5, a centrifugal clutch 106 constituting a winding mechanism 42 is provided in the second housing portion 40 of the case 32. The centrifugal clutch 106 includes a rotor 108 that is formed in a bottomed cylindrical shape and has an inside opened to one side (arrow A side). The rotor 108 is rotatably supported by the case 32 with the axial center portion of the bottom wall being rotatably supported by a support shaft 110 attached to the case 32. In addition, a cover 112 formed in a disk shape from a metal plate material is attached to the opening of the rotor 108 with a screw. Further, spur external teeth 114 are formed on the outer peripheral portion of the rotor 108, and the external teeth 114 mesh with the external teeth 100 of the gear portion 98 of the adapter 94 described above. Therefore, when the adapter 94 is rotated around one axis (in the direction of arrow I), the rotor 108 can be rotated around one axis (in the direction of arrow K) and the adapter 94 is rotated around the axis (in the direction of arrow J). The rotor 108 is rotated around the axis in the other direction (arrow L direction).

  On one side (the arrow A side) of the rotor 108, a gear 116 that is formed in a columnar shape and forms the centrifugal clutch 106 is provided. The gear 116 has an axial center portion rotatably supported by the support shaft 110 and is rotatably supported by the case 32, and can rotate relative to the rotor 108. A spur tooth 118 is formed on the outer peripheral portion of one side (arrow A side) of the gear 116, and the first housing portion 38 and the second housing portion 40 communicate with each other in the vicinity of the outer tooth 118. The external teeth 118 are meshed with the outer periphery of the drive gear 46. For this reason, when the gear 116 is rotated around the axis in one direction (arrow K direction), the drive gear 46 can be rotated in the pull-out direction (arrow H direction), and the gear 116 is rotated around the axis in the other direction (arrow L direction). , The drive gear 46 is rotatable in the winding direction (arrow G direction).

  Further, ratchet teeth 120 are formed on the outer peripheral portion of the other end (arrow B side) of the gear 116. The ratchet teeth 120 are arranged inside the rotor 108 via a circular hole 122 formed in the axial center portion of the cover 112.

  Inside the rotor 108, a pair of weights 124 that are each formed in a substantially semicircular plate shape by a metal material such as iron and constitute the centrifugal clutch 106 are disposed. The pair of weights 124 are formed to have the same weight, and are disposed on opposite sides (180 ° opposite sides) along the circumferential direction of the rotor 108. A circular bearing hole 126 is formed at one end in the circumferential direction of the pair of weights 124, and a cylindrical shaft portion 128 protruding from the bottom wall of the rotor 108 is rotatably fitted in the bearing hole 126. Match. Accordingly, the pair of weights 124 are supported by the rotor 108 so as to be rotatable about the shaft portion 126 in the radial direction of the rotor 108.

  The pair of weights 124 are urged radially inward of the rotor 108 by a pair of torsion coil springs 130 attached to the bottom wall of the rotor 108, respectively, and are usually held radially inward of the rotor 108. Yes. Further, the pair of weights 124 are formed with meshing protrusions 132 at positions facing the ratchet teeth 118 of the gear 116 described above. The pair of meshing protrusions 132 are separated from the ratchet teeth 120 in a state where the pair of weights 124 are held on the radially inner side of the rotor 108.

  Between the pair of weights 124 and the cover 112, a sheet 134 formed in a ring shape by a resin material plate is disposed, and the pair of weights 124 is prevented from directly rubbing against the cover 112. .

  Here, when the rotor 108 is rotated around the axis in the other direction (arrow L direction), the pair of weights 124 supported by the rotor 108 is rotated around the axis of the rotor 108 following the rotor 108. At this time, centrifugal force acts on the pair of weights 124. Therefore, when the centrifugal force acting on the pair of weights 124 exceeds a predetermined value (when the rotational speed of the rotor 108 exceeds a predetermined value), the pair of weights 124 resists the biasing force of the pair of torsion coil springs 130. The rotor 108 rotates outward in the radial direction. As described above, when the pair of weights 124 rotate outward in the radial direction of the rotor 108, the pair of meshing protrusions 132 provided on the pair of weights 124 mesh with the ratchet teeth 120 of the gear 116. In a state where the pair of meshing protrusions 132 mesh with the ratchet teeth 120, the rotor 108 and the gear 116 are integrally connected via the pair of weights 124, and the rotor 108, the pair of weights 124, and the gear 116 are integrated. It is made rotatable.

  When the rotor 108 is rotated around one axis (in the direction of the arrow K) from the state where the pair of meshing protrusions 132 mesh with the ratchet teeth 120 of the gear 116, the pair of meshing protrusions 132 and the ratchet teeth 120 are meshed. The pair of weights 124 are rotated inward in the radial direction of the rotor 108 by the urging force of the pair of torsion coil springs 130. Thereby, the relative idle rotation of the rotor 108 and the gear 116 is possible.

  As shown in FIG. 1, in the motor retractor 10 according to the present embodiment, power supply control to the motor 48 is performed by the control device 138. The control device 138 includes a driver 140 and an ECU 142. The motor 48 is electrically connected to a battery 144 mounted on the vehicle via a driver 140, and current from the battery 144 is supplied via the driver 140. The driver 140 is connected to the ECU 142, and the ECU 142 is configured to control the presence / absence of power supply to the motor 48 via the driver 140, the direction and magnitude of the supply current.

  The ECU 142 is connected to a buckle switch 146 that outputs a signal according to whether or not the occupant is wearing the webbing 28 and a front monitoring device 148 that outputs a signal according to the distance between the vehicle and an obstacle ahead of the vehicle. .

  The buckle switch 146 outputs an ON signal to the ECU 142 when the tongue plate into which the webbing 28 is inserted is connected to a buckle device (both not shown) (when the webbing 28 is attached to the occupant). An OFF signal is output to the ECU 142 when the connection state of the plate to the buckle device is released (when the webbing 28 is attached to the occupant). That is, the buckle switch 146 is configured to output either the ON signal or the OFF signal to the ECU 142 in accordance with whether or not the tongue plate and the buckle device corresponding to whether or not the webbing 28 is attached to the occupant.

  The front monitoring device 148 includes an infrared sensor 150 provided near the front end of the vehicle. The infrared sensor 150 emits infrared rays in front of the vehicle, and is referred to as an “obstacle” for convenience, including other vehicles and obstacles that are running or stopped in front of the vehicle (hereinafter, including other vehicles that are running or stopped). ) To receive the reflected infrared light.

  Further, the forward monitoring device 148 includes a calculation unit 152. The calculation unit 152 calculates the distance to the obstacle based on the time required to return to the infrared sensor 150 after being reflected by the obstacle after the infrared ray is emitted from the infrared sensor 150. In addition, the calculation unit 152 outputs an obstacle detection signal Os to the ECU 142 based on the calculation result. The obstacle detection signal Os is set to a low level if the distance to the obstacle is equal to or greater than a predetermined value, and is set to a high level if the distance to the obstacle is less than the predetermined value. For example, a vehicle collision) is predicted.

  Here, when the signal input from the buckle switch 146 changes from the OFF signal to the ON signal, the ECU 142 outputs a control signal for starting power supply to the motor 48 to the driver 140. The driver 140 to which the control signal is input supplies the motor 48 with a positive current F having a current value I 1 from the battery 144. In this case, the motor 48 is driven in the forward direction for a predetermined time, and the output shaft 50 and the output gear 52 are rotated around the axis for one predetermined time (in the direction of arrow C) at the first speed. Thereby, the tension reducer mechanism 60 is operated (turned on).

  Further, when the signal input from buckle switch 146 changes from the ON signal to the OFF signal, ECU 142 outputs a control signal for starting power supply to motor 48 to driver 140. The driver 140 to which the control signal is input supplies the motor 48 with a current F in the reverse direction of the current value I1 from the battery 144. In this case, the motor 48 is driven in the reverse direction for a predetermined time, and the output shaft 50 and the output gear 52 are rotated around the axis for the predetermined time at the first speed in the other direction (arrow D direction). Thereby, the operation of the tension reducer mechanism 60 is released (turned off).

  In addition, when the obstacle detection signal Os input from the calculation unit 152 changes from the Low level to the High level, the ECU 142 operates (turns on) the winding mechanism 42 to start the power supply to the motor 48. The signal is output to the driver 140. The driver 140 to which the operation signal is input supplies the motor 48 with a current R in the reverse direction of the current value I2 from the battery 144. In this case, the current value I2 of the current R is set larger than the current value I1 of the current F, the motor 48 is driven in a reverse direction for a specific time, and the output shaft 50 and the output gear 52 are It is rotated around the specific time axis in the second direction (arrow D direction) at a second speed faster than the first speed.

  Further, the ECU 142 outputs an operation signal for starting power supply to the motor 48 to the driver 140 after the winding mechanism 42 is operated and the motor 48 is driven in the reverse direction for a specific time. The driver 140 to which the operation signal is input supplies the motor 48 with a positive current F having a current value I 1 from the battery 144. In this case, the motor 48 is driven in the forward direction for a specified time, and the output shaft 50 and the output gear 52 are rotated in one direction (in the direction of arrow C) around the specified time axis at the first speed. Thereby, the winding mechanism 42 is reset.

  Next, the operation of the present embodiment will be described.

  In the motor retractor 10 having the above-described configuration, the tension reducer mechanism 60 is deactivated (turned off) when the webbing 28 is fully wound on the spool 20, and the locking protrusion 76 of the cam 72 is formed in the case. As shown in FIG. 9A, the minimum diameter portion of the cam portion 74 of the cam 72 is opposed to the restricting body 62 as a result of coming into contact with the other end (in the direction of arrow F) around the axis of the 32 locking recesses 78. The first pawl 82 and the second pawl 84 are arranged at the rotational position opposite to the restricting body 62 by the urging force of the return spring 54, and the other end of the second pawl 84 is separated from the outer periphery of the restricting body 62. Yes. For this reason, the spool 20, the torsion coil spring 66, and the restricting body 62 can be rotated together, and a rotational force in the pull-out direction (arrow H direction) is applied to the spool 20 by the biasing force of the torsion coil spring 66. There is no.

  As a result, when the webbing 28 is pulled from the state in which the webbing 28 is completely wound on the spool 20, the spool 20 resists the biasing force of the spiral spring 44 that biases the spool 20 in the winding direction (arrow G direction). The webbing 28 is pulled out while rotating in the pulling direction (arrow H direction).

  In this way, with the webbing 28 pulled out, the tongue plate is inserted into the buckle device while the webbing 28 is hung around the front of the occupant seated on the seat, and the tongue plate is connected to the buckle device. The webbing 28 is attached to the occupant's body.

  When the tongue plate is connected to the buckle device and the signal input from the buckle switch 146 to the ECU 142 changes from the OFF signal to the ON signal, the output gear 52 of the motor 48 is rotated around the axis for a predetermined time (arrow C) at the first speed. Direction). For this reason, the drive gear 56, the slip spring 70, and the cam 72 are rotated around one axis (in the direction of arrow E), and the locking projection 76 of the cam 72 is rotated around the axis of the locking recess 78 of the case 32 (in the direction of arrow E). ) By contacting the side end, the maximum diameter portion of the cam portion 74 of the cam 72 faces the restricting body 62 as shown in FIGS. 9B and 9C. When the locking projection 76 contacts one end (in the direction of arrow E) around the axis of the locking recess 78, the cam 72 and the slip spring 70 are prevented from rotating in one direction (in the direction of arrow E). Thus, the drive gear 56 is rotated relative to the slip spring 70 and the cam 72 in one direction around the axis (in the direction of arrow E) (slip).

  When the maximum diameter portion of the cam portion 74 of the cam 72 faces the restricting body 62, the first pawl 82 and the second pawl 84 are moved to the rotating position on the restricting body 62 side against the urging force of the return spring 54. The tension reducer mechanism 60 is actuated (turned on) when the other end of the second pawl 84 is in contact with the outer periphery of the restricting body 62.

  For this reason, after the webbing 28 is mounted on the occupant, as shown in FIG. 9B, when the restricting body 62 is rotated together with the spool 20 in the winding direction (arrow G direction) by the urging force of the spiral spring 44. The surface of the restricting convex portion 64 of the restricting body 62 on the winding direction (arrow G direction) side is locked to the other end of the second pawl 84, and the restricting body 62 is wound in the winding direction (arrow G direction). Rotation is prevented. Thereby, as the spool 20 is rotated in the winding direction (arrow G direction) by the urging force of the spiral spring 44, the rotational force in the pulling direction (arrow H direction) of the spool 20 by the urging force of the torsion coil spring 66 is applied. And the rotational force in the winding direction (arrow G direction) of the spool 20 due to the biasing force of the spiral spring 44 is limited by the biasing force of the torsion coil spring 66, and the winding direction of the spool 20 (arrow G direction). The rotational force to is weakened. Therefore, the pressure received by the occupant from the webbing 28 can be reduced, and the occupant can feel better wearing the webbing 28.

  Further, the webbing 28 is pulled out from the spool 20 in a state where the webbing 28 is attached to the occupant, and twisted as compared with the rotational force in the winding direction (arrow G direction) of the spool 20 due to the urging force of the spiral spring 44. The rotational force in the pull-out direction (arrow H direction) of the spool 20 due to the biasing force of the coil spring 66 is increased, and the restricting body 62 is pulled in the pull-out direction (arrow as shown in FIG. 9C) by the biasing force of the torsion coil spring 66. When rotating in the H direction), the second pawl 84 is guided by the surface of the restricting convex portion 64 of the restricting body 62 on the pulling direction (arrow H direction) side and resists the urging force of the return spring 54. By rotating to the opposite side of the restricting body 62 with respect to the one pawl 82, the restricting convex portion 64 gets over the other end of the second pawl 84, and the restricting body 62 rotates in the pull-out direction (arrow H direction). Allowed. Thereby, the rotational force in the pulling-out direction (arrow H direction) of the spool 20 by the biasing force of the torsion coil spring 66 is compared with the rotational force in the winding direction (arrow G direction) of the spool 20 by the biasing force of the spiral spring 44. Can be prevented, and the webbing 28 attached to the passenger can be prevented from unnecessarily loosening.

  On the other hand, when the tongue plate is removed from the buckle device (the wearing of the webbing 28 on the occupant's body is released) and the signal input from the buckle switch 146 to the ECU 142 changes from the ON signal to the OFF signal, the output of the motor 48 The gear 52 is rotated around the axis for the predetermined time at the first speed in the other direction (arrow D direction). For this reason, the drive gear 56, the slip spring 70, and the cam 72 are rotated around the axis to the other side (arrow F direction), and the locking projection 76 of the cam 72 is rotated around the axis line of the locking recess 78 of the case 32 (arrow F direction). ) By contacting the side end, the minimum diameter portion of the cam portion 74 of the cam 72 faces the restricting body 62 as shown in FIG. When the locking projection 76 contacts the other end (in the direction of arrow F) around the axis of the locking recess 78, the cam 72 and the slip spring 70 are prevented from rotating in the other direction (in the direction of arrow F). Thus, the drive gear 56 is rotated relative to the slip spring 70 and the cam 72 in the other direction (arrow F direction) around the axis (slip).

  When the minimum diameter portion of the cam portion 74 of the cam 72 faces the restricting body 62, the first pawl 82 and the second pawl 84 are arranged at the rotational position opposite to the restricting body 62 by the urging force of the return spring 54. Then, the other end of the second pawl 84 is separated from the outer periphery of the limiting body 62, so that the operation of the tension reducer mechanism 60 is released (turned off). For this reason, the spool 20, the torsion coil spring 66, and the restricting body 62 can be rotated together, and a rotational force in the pull-out direction (arrow H direction) is applied to the spool 20 by the biasing force of the torsion coil spring 66. If the tongue plate is removed from the buckle device, the entire webbing 28 is wound around the spool 20 by the urging force of the spiral spring 44.

  As described above, the output gear 52 of the motor 48 is rotated at the first speed, and the rotor 108 is rotated through the intermediate gear 88, the clutch spring 104, and the adapter 94 in the winding mechanism 42, whereby the rotor Even if a centrifugal force acts on the pair of weights 124 supported by 110, the centrifugal force acting on the pair of weights 124 causes the pair of weights 124 to resist the biasing force of the pair of torsion coil springs 130. It does not increase enough to rotate radially outward. Accordingly, the pair of weights 124 are held radially inward of the rotor 108 by the urging force of the pair of torsion coil springs 130, and the pair of meshing protrusions 132 provided on the pair of weights 124 are the ratchet teeth 120 of the gear 116. The rotor 108 is idled relative to the gear 116 together with the pair of weights 124, the pair of torsion coil springs 130, the seat 134, and the cover 112.

  Further, when the vehicle is in a running state (a state in which the webbing 28 is attached to the occupant and the tension reducer mechanism 60 is activated (turned on)), the calculation unit is based on the detection result of the infrared sensor 150 of the front monitoring device 148. 152 calculates the distance to the obstacle ahead of the vehicle. For example, when there is no obstacle ahead of the vehicle, or there is an obstacle but the distance from the obstacle to the vehicle is equal to or greater than a predetermined value, a low level signal is output from the calculation unit 152. On the other hand, when the distance from the vehicle to the obstacle ahead is less than the predetermined value, a high level signal is output from the calculation unit 152, and an emergency situation of the vehicle is predicted.

  When a high level signal is input from the calculation unit 152 to the ECU 142, the winding mechanism 42 is activated (turned on), and the output gear 52 of the motor 48 is rotated around the specific time axis at the second speed (arrow). (D direction).

  When the output gear 52 rotates around the axis in the other direction (arrow D direction) at the second speed, the intermediate gear 88 of the overload mechanism 86 with the external gear 92 meshed with the output gear 52 moves around the axis line in the other direction (arrow J direction). Rotate.

  The rotation of the intermediate gear 88 is transmitted to the adapter 94 via the clutch spring 104, and the adapter 94 rotates around the axis in the other direction (arrow J direction). Therefore, the rotor 108 of the centrifugal clutch 106 in which the external teeth 114 are engaged with the external teeth 100 of the gear portion 98 of the adapter 94 is rotated around the axis in the other direction (arrow L direction), and a pair of weights 124 supported by the rotor 110. A centrifugal force of a predetermined value or more acts on. For this reason, the pair of weights 124 are rotated outward in the radial direction of the rotor 108 against the biasing force of the pair of torsion coil springs 130, and the pair of meshing protrusions 132 provided on the pair of weights 124 serve as gears. It meshes with 116 ratchet teeth 120. Thereby, the winding mechanism 42 is communicated, and the rotation of the rotor 108 is transmitted to the gear 116 through the pair of weights 124, and the gear 116 rotates around the axis in the other direction (arrow L direction).

  Therefore, the drive gear 46 meshed with the external teeth 118 of the gear 116 is rotated in the winding direction (arrow G direction), and the spool 20 is rotated in the winding direction (arrow G direction). The rotation of the spool 20 in the winding direction (arrow G direction) causes the webbing 28 to be wound around the spool 20, whereby loosening of the webbing 28, so-called “slack” is eliminated, and the webbing 28 restrains the passenger body. The force is improved (so-called “pretensioner mechanism”). Therefore, for example, when the webbing 28 is wound on the spool 20, even if the vehicle suddenly decelerates (rapid braking) and the occupant moves forward, the webbing 28 resists the inertial force of the occupant. Can be forcibly wound up.

  Further, when the winding mechanism 42 is operated (turned ON) and the webbing 28 is wound around the spool 20 and a torque greater than a set value is applied to the spool 20 (for example, so-called “slack”). Is eliminated, and the body of the occupant is obstructed and the webbing 28 can no longer be wound up), the clutch spring 104 held by the friction force against the holding portion 102 of the adapter 94 is By idle (slip) relative to the adapter 94, the transmission of rotation between the adapter 94 and the intermediate gear 88 (output gear 52) is disconnected, and both of them idle relatively. As a result, the spool 20 connected to the adapter 94 via the rotor 108, the pair of weights 124 and the gear 116 is rotated in the winding direction (arrow G direction) with an excessive force by the driving force of the motor 48. It is possible to prevent the webbing 28 from tightening the occupant's body with an excessive force.

  Further, in the event of an emergency of the vehicle, the lock mechanism provided in the case 22 prevents the spool 20 from rotating in the pull-out direction (arrow H direction) and prevents the webbing 28 from being pulled out. As a result, the restraining force of the webbing 28 on the passenger body is limited.

  After the winding mechanism 42 is activated (turned on) and the output gear 52 of the motor 48 is rotated around the specific time axis in the other direction (arrow D direction) (for example, after an emergency situation of the vehicle is avoided) The output gear 52 of the motor 48 is rotated around the specified time axis in one direction (arrow C direction) at the first speed. Therefore, the intermediate gear 88, the clutch spring 104, and the adapter 94 are rotated around one axis (in the direction of arrow I), and the rotor 108 is rotated around one axis (in the direction of arrow K). The engagement state between the pair of engagement protrusions 132 provided and the ratchet teeth 120 of the gear 116 is released, and the pair of weights 124 rotate inward in the radial direction of the rotor 108 by the biasing force of the pair of torsion coil springs 130. Is done. As a result, the communication of the winding mechanism 42 is released, and the relative rotation of the rotor 108 and the gear 116 becomes possible, and the spool 20 and the output shaft 50 of the motor are connected by the winding mechanism 42 (centrifugal clutch 106). Is released, and the winding mechanism 42 is reset.

  When the winding mechanism 42 is operated (turned on), the output gear 52 of the motor 48 is rotated around the axis in the other direction (arrow D direction), so that the operation of the tension reducer mechanism 60 is released. Is done. Thereafter, when the winding mechanism 42 is reset, the output gear 52 of the motor 48 is rotated around one axis (in the direction of arrow C), whereby the tension reducer mechanism 60 is operated.

  Here, in the motor retractor 10 according to the present embodiment, the winding mechanism 42 and the tension reducer mechanism 60 are integrally disposed in the case 32 outside the frame 12. For this reason, the motor retractor 10 can be reduced in size.

  Furthermore, since the tension reducer mechanism 60 can be activated and deactivated by driving the motor 48 that activates the winding mechanism 42, it is necessary to separately provide a drive device such as a solenoid for activating and deactivating the tension reducer mechanism 60. Therefore, the motor retractor 10 can be further downsized.

  Further, as described above, when the winding mechanism 42 is reset after the operation, the output gear 52 of the motor 48 is rotated around one axis (in the direction of arrow C), whereby the tension reducer mechanism 60 is operated. The rotational force in the winding direction (arrow G direction) of the spool 20 by the urging force of the spiral spring 44 is limited by the urging force of the torsion coil spring 66. For this reason, it is not necessary to operate the tension reducer mechanism 60 again by driving the motor 48 after the winding mechanism 42 is reset, and a load is generated on the motor retractor 10 (the motor 48, the winding mechanism 42 and the tension reducer mechanism 60). Opportunities can be reduced and the durability of the motor retractor 10 can be improved.

It is a schematic front view which shows the whole structure of the motor retractor which concerns on embodiment of this invention. It is a disassembled perspective view which shows the whole structure of the motor retractor which concerns on embodiment of this invention. It is a disassembled perspective view which shows the structure of the principal part of the motor retractor which concerns on embodiment of this invention. It is a sectional side view which shows the structure of the principal part of the motor retractor which concerns on embodiment of this invention. It is sectional drawing (5-5 sectional view taken on the line of FIG. 4) which shows the structure of the motor retractor which concerns on embodiment of this invention. FIG. 6 is a cross-sectional view (cross-sectional view taken along line 6-6 in FIG. 4) illustrating the configuration of the motor retractor according to the embodiment of the present invention. FIG. 7 is a cross-sectional view (cross-sectional view taken along line 7-7 in FIG. 4) showing the configuration of the motor retractor according to the embodiment of the present invention. It is a disassembled perspective view which shows the structure of the principal part of the tension reducer mechanism in the motor retractor which concerns on embodiment of this invention. (A) thru | or (C) is the side view seen from the other side which shows the structure of the tension reducer mechanism in the motor retractor which concerns on embodiment of this invention.

Explanation of symbols

10 Motor retractor 12 Frame (arrangement member)
20 Spool (winding shaft)
28 Webbing 42 Winding mechanism 44 Spiral spring (biasing means)
48 Motor 60 Tension reducer mechanism (limit mechanism)

Claims (3)

The webbing is wound by being rotated in the winding direction, and the winding shaft from which the webbing is pulled by being rotated in the pulling direction;
An arrangement member in which the winding shaft is arranged;
A biasing means connected to the winding shaft and imparting a biasing force in the winding direction to the winding shaft;
A motor capable of being driven in one direction and the other direction;
A winding mechanism that is disposed outside the arrangement member and is provided between the winding shaft and the motor, and rotates the winding shaft in the winding direction when the motor is driven in one direction. When,
The winding mechanism and while being integrally disposed on the outside of the placement member, provided between said winding shaft motor, said from the urging means by the motor is driven in the other direction The transmission of the urging force to the winding shaft is limited to limit the application of the urging force to the winding shaft by the urging means , and the motor is driven in one direction so that the urging means can A limiting mechanism that permits transmission of the urging force to the winding shaft and permits the urging means to apply the urging force to the winding shaft ;
A webbing take-up device comprising:   In the winding mechanism, the motor is driven in one direction to connect the winding shaft and the motor to rotate the winding shaft in the winding direction, and the motor is driven in the other direction. The webbing take-up device according to claim 1, wherein communication between the take-up shaft and the motor is released.   The motor is driven in the other direction when the webbing is attached to the occupant, and the motor is driven in one direction when the webbing is released from the occupant. The webbing take-up device according to claim 1 or 2.

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